some themes omitting special characters?

just wondering why these two themes behave differently?

Post title: Întreb?ri ?i r?spunsuri - here the special characters are omitted from the slug: http://stefanstoica.zice.ro/uncategorized/ntrebri-i-rspunsuri/

Post title: ?i-o pun eu? - here the special characters are converted: http://anne.zice.ro/limba-asta/ti-o-pun-eu/

i it the theme or what is happening here? can someone explain?